Potentiodynamic polarization measurements

The goals of this laboratory session are to introduce you to potentiodynamic polarization measurements for the determination of localized susceptibility, dem-onslralc the effect of the presence of non-CL ions on pitting, and present examples of metastable pitting (one type of electrochemical noise ). 

Potentiodynamic polarization measurement is an effective electrochemical technique in characterizing film formed on a metal surface under various redox conditions. The electrochemical polarization measurements were... 

What do you expect in a potentiodynamic polarization measurement if you have corrosion inhibitor in a CMP slurry, and what are the reasons for expecting such behavior ... 

ASTM G61-78, Standard Practice for Conduct-ing Cyclic Potentiodynamic Polarization Measurements for Localized Corrosion, American Society for Testing and Materials, Philadelphia, Pa. 

G61-86, Conducting cyclic potentiodynamic polarization measurements for localized corrosion susceptibility of iron-, nickel-, or cobalt-based alloys, Annual Book of ASTM Standards, ASTM International, Philadelphia, Pa., 2000, p. 240, Vol. 3.02. 

Tafel extrapolation procedure Potentiodynamic Polarization Measurements Electrochemical Impedance Spectroscopy... 

The potentiodynamic polarization technique is used to determine the potential region at which the alloy or the metal is passive when exposed to a particular environment. It estimates both the ability of the material to spontaneously passivate as well as the critical current density necessary for its passivation. Potentiodynamic polarization measurements identify the corrosion properties of passivating metals and alloys and are very usefirl in predicting how a material will behave when exposed to a corrosive environment. The method estimates the corrosion active region, the onset of passivation, the critical current density, the primary passive potential, the current in the passive region, and the voltage span of the passive region. 

ASTM G 61-86, Standard Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements for Localized Corrosion Susceptibility of Iron-, Nickel-, or Cobalt-Based Alloys, ASTM International, West Conshohocken, PA, 2003. 

F 2129 Standard Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements to Determine the... 

Other DC methods that are quite simple to use and provide important information to the corrosion scientist include polarization resistance (ASTM G 59, Practice for Conducting Potentiodynamic Polarization Resistance Measurements), potentiostatic and potentiodynamic polarization measurements (ASTM G 5, Standard Reference Test Method for Making Potentiostatic and Potentiodynamic Anodic Polarization Measurements), cyclic polarization measurements (ASTM G 61, Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements for Localized Corrosion Susceptibility of Iron-, Nickel-, or Cobalt-based Alloys), and galvanic current monitoring. These DC techniques can be used to estimate the reactivity of a mateiieJ in a peurticular environment, to determine the corrosion rate of a materieJ in a particular environment, and/or to determine the susceptibility of a material to localized corrosion. 

Potentiodynamic polarization measurements are quite appropriate for determination of the pitting susceptibility of aluminum coatings, and/or the corrosion current density/ corrosion rate of coated steel products in general. ASTM G 102, Practice for Calculation of Corrosion Rates and Related Information from Electrochemical Measurements, describes the calculation of corrosion rates and other information from electrochemical measurements. Another example of the use of DC electrochemical methods to examine the corrosion performance of coated sheet materials is a study by D. A. Jones et al. [48]. The study used polarization resistance measurements to examine the mechanism of steel and coated sheet degradation under conditions of alternate immersion. Jones compared the polarization resistance of samples of low-carbon steel, unpainted galvanized, aluminum-coated, and Zn-Ni alloy coated steel during continuous immersion and alternate immersion. Alternate immersion cyclic exposure produced a thick oxide that led to significant underfilm attack. Jones found that phosphate pretreatment tends to increase the resistance of these materials to underfilm attack. This study is an excellent example of the way electrochemical measurements can be used as a complement to other techniques to elucidate mechanistic information. 

Mass loss measurements established high rates of corrosion for steel and copper. Potentiodynamic polarization measurements showed that in SRB environment, copper becomes anodic to steel. 

ANSI/ASTM Designation G51. Annual Book of Standards, Vol. 02, 03. Conducting Cyclic Potentiodynamic Polarization Measurement for Localized Corrosion. (American Society for Testing of Materials, 2002)... 

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